<PAGE>
 
                                                                   Exhibit 10.25
 
                            PARKRIDGE OFFICE CENTER
                                  BUILDING ONE


                                  OFFICE LEASE
                                        



LANDLORD:       PARK RIDGE ONE ASSOCIATES

TENANT:              MASTECH SYSTEMS CORPORATION



Dated for reference purposes as of :   October 14, 1998
 
 
<PAGE>
 
                                PARK RIDGE ONE ASSOCIATES
                                 Basic Lease Information

Lease Date:                  October 14, 1998
                             ----------------

Tenant:                      Mastech Systems Corporation
                             ---------------------------

Address:                     Suite 500
                             ---------
                             Park Ridge One, Pittsburgh, PA 15275
                             ------------------------------------

     Contact Person:         Jeff McCandless, Vice President of Finance
                             ------------------------------------------
     with a copy to:  Daniel Daugherty, Manager of Contracts and Legal Affairs
                      --------------------------------------------------------
     Phone:
            ------------------------------------------------------------------

Landlord:                    Park Ridge One Associates
                             -------------------------

     Address:                C/O Grubb & Ellis Management Services, Inc.
                             -------------------------------------------
                             600 Six PPG Place
                             -----------------
                             Pittsburgh, PA 15222
                             --------------------
     Phone:            (412) 281-0100
                       --------------

Building:                    As described in Paragraph 1.1 of the Lease.
                             -------------------------------------------

Total Rentable Area of
Building Office Space:       99,066 Rentable Square Feet
                             ---------------------------

     Suite:                  500 and 130
                             -----------
     Floor(s):               1st and 5th
                             -----------
     Rentable Area:          25,599
                             ------

Term:                        5 years
                             -------
 
Proposed Commencement Date:  This lease shall commence sixty (60) days after 
                             CNG Energy Services Corporation vacates the 
                             property in full and based on a walkthrough and 
                             written signoff by Tenant, but not later than
                             December 15, 1998.
 
Expiration Date (subject
to Lease Provisions):        December 14, 2003
                             -----------------

Annual Base Rental:          $20.50 per rentable square feet.  Five Hundred
                             ----------------------------------------------
                             Twenty-Four Thousand Seven Hundred Seventy-Nine
                             -----------------------------------------------
                             and 50/100 ($524,779.50) Dollars
                             --------------------------------
 
<PAGE>
 
Tenant's Share of Excess
Expenses (Subject to
Lease Provisions):           25.8%
                             -----

Tenant's Share of Excess
Taxes (Subject to Lease
Provisions):                 25.8%
                             -----

Excess Taxes Base:           Base Year is 1999
                             -----------------

Excess Expenses Base:        Base Year is 1999
                             -----------------

Use:                         General office
                             --------------

Security Deposit:            None
                             ----

Date Prior to Which
Tenant Shall Deliver Plans:  None
                             ----

Other:
       -----------------------------------------------------------------------


Broker:            Grubb & Ellis Company, 600 PPG Place, Pittsburgh, PA  15222
                   -----------------------------------------------------------
                   Oxford Development Company, One Oxford Center, Pgh., PA 15219
                   -------------------------------------------------------------

The foregoing Basic Lease Information is hereby incorporated into and made a
part of this Lease.

Park Ridge One Associates,
a Delaware limited partnership      Mastech Systems Corporation

By:  ________________________________  ______________________________________
     a Delaware corporation
     General Partner

By:  ________________________________  By:  ___________________________________
 
Its: ________________________________  Its: ___________________________________

AUTHORIZED AGENT FOR
PARK RIDGE ONE ASSOCIATES
a Pennsylvania limited partnership
<PAGE>
 
                              TABLE OF CONTENTS
 
ARTICLE                                                                 PAGE
 
1.   PREMISES.............................................................1

2.   TERM.................................................................1

3.   ANNUAL BASE RENTAL; ADDITIONAL RENT..................................2

4.   ADDITIONAL RENT FOR EXCESS OPERATING EXPENSES AND TAXES..............3

5.   TERMS OF PAYMENT.....................................................7

6.   CONSTRUCTION OF THE PREMISES.........................................7

7.   COMMON AREA MAINTENANCE..............................................8

8.   CONDUCT OF BUSINESS BY TENANT........................................8

9.   ALTERATIONS AND TENANT'S PROPERTY....................................8
 
10.  REPAIRS..............................................................9
 
11.  LIENS...............................................................10
     
12.  COMPLIANCE WITH LAWS AND INSURANCE REQUIREMENTS.....................11

                                      (i)
<PAGE>
 
13.  SUBORDINATION.......................................................11
 
14.  INABILITY TO PERFORM................................................12
                                                                         
15.  DESTRUCTION.........................................................12
                                                                         
16.  EMINENT DOMAIN......................................................14
                                                                         
17.  ASSIGNMENT..........................................................15
                                                                         
18.  SUBLETTING..........................................................17
                                                                         
19.  UTILITIES...........................................................18
 
20.  DEFAULT.............................................................20
                                                                         
21.  INDEMNITY...........................................................23
                                                                         
22.  TENANT'S INSURANCE..................................................24
                                                                         
23.  LIMITATION OF LANDLORD'S LIABILITY..................................24
                                                                         
24.  ACCESS TO PREMISES..................................................25
                                                                         
25.  NOTICES.............................................................25
                                                                         

                                      (ii)
<PAGE>
 
26.  NO WAIVER...........................................................26
 
27.  TENANT'S CERTIFICATES...............................................26
                                                                         
28.  RULES AND REGULATIONS...............................................27
                                                                         
29.  SECURITY DEPOSIT....................................................27
                                                                         
30.  AUTHORITY...........................................................27
                                                                         
31.  MISCELLANEOUS.......................................................28
 

                                     (iii)
<PAGE>
 
     EXHIBIT A - FLOOR PLAN

     EXHIBIT B - DESCRIPTION OF LAND

     EXHIBIT C - WORK AGREEMENT

     EXHIBIT D - FORM OF SUBORDINATION OF MORTGAGE AGREEMENT

     EXHIBIT E - RULES AND REGULATIONS

     EXHIBIT F - LICENSE AGREEMENT

                                      (iv)
<PAGE>
 
                                 OFFICE LEASE

     THIS LEASE is made and entered into this 14th day of October, 1998, by and
between PARK RIDGE ONE ASSOCIATES L.P., a Pennsylvania limited partnership,
(herein called "Landlord"), and MASTECH SYSTEMS CORPORATION (herein called
"Tenant").

                                 WITNESSETH:

     Landlord and Tenant hereby covenant and agree as follows:

     1.  PREMISES

     1.1  Upon and subject to the terms, covenants and conditions hereinafter
set forth, Landlord hereby leases to Tenant and Tenant hereby hires from
Landlord those premises (herein called the "Premises") in the building known as
Park Ridge Office Center, Building One, in Findlay Township, Pennsylvania
(herein called the "Building") , comprising the area substantially as shown on
the floor plan or plans attached hereto as Exhibit A. The Premises are located
on the floors of the Building that are specified in the Basic Lease information.
The term "Building" includes the LAND upon which the Building stands and which
is described in Exhibit B attached hereto (the "Land"), all easements and rights
appurtenant to the Land and Building, all parking facilities located on the
Land, and all improvements serving the Building and designated from time-to-time
by Landlord as Land or common areas appurtenant to the Building, together with
utilities, facilities, drives, walkways and other amenities appurtenant to or
servicing the Building.

     2.  TERM

     2.1  The Premises are leased for a term (herein called the "Term") to
commence and end on the dates respectively specified in the Basic Lease
Information, unless the Term shall sooner terminate as hereinafter provided.
If, on or prior to the date set forth in the Basic Lease Information for the
commencement of the Term (the "Proposed Commencement Date") , Landlord fails to
deliver possession of the Premises, either (a) because Landlord's Work (as
hereinafter defined in Article 6 hereof) shall not have been substantially
completed, or (b) because a previous occupant is holding over, or (c) because of
any other cause or reason beyond the reasonable control of Landlord, then the
following provisions shall apply; (i) the Term shall not commence on the
Proposed Commencement Date but shall, instead, commence on the date fixed by
Landlord in a notice to Tenant, which notice shall state that the Premises are,
or prior to the commencement date fixed in such notice will be, substantially
completed and ready for occupancy by Tenant; (ii) neither the validity of this
Lease nor the obligations of Tenant under this Lease shall be affected by such
failure to deliver possession, except that the Term shall begin as provided in
clause (i) above; (iii) Tenant shall have no claim against Landlord failure to
deliver possession of the Premises on the date originally fixed therefor; (iv)
in no event shall the expiration date of the Term be extended beyond the date
specified in the Basic Lease Information.

     2.2  The dates upon which the Term shall commence and terminate pursuant to
this Article 2 are herein called the "Commencement Date" and the "Expiration
Date" respectively.
<PAGE>
 
     2.3  Notwithstanding anything to the contrary herein contained, in the
event that the Term shall not have commenced on or before such date as shall be
three (3) months from the Commencement Date set forth in the Basic Lease
Information and such delay in commencement shall not have been caused by the
Tenant or any event included in Section 31.16 hereof, then this Lease shall be
automatically terminated without any further act of either party hereto and both
parties hereto shall be released from all obligations hereunder.  If such delay
shall have been caused by the Tenant or an event included in Section 31.16 then
this Lease may only be terminated at the option of the Landlord.

     2.4  Tenant shall have a five (5) year renewal option at a rate consistent
with the then current Base Rental Rates for Class A suburban office properties
in Pittsburgh, Pennsylvania.

     3.  ANNUAL BASE RENTAL; ADDITIONAL RENT

     3.1  Tenant shall pay to Landlord during the Term the Annual Base Rental
specified in the Basic Lease Information (herein called the "Annual Base
Rental"), which sum shall be payable by Tenant in equal consecutive monthly
installments on or before the first day of each month, in advance, at the
address specified for Landlord in the Basic Lease Information, or such other
place as Landlord shall designate, without any prior demand therefor and without
any deductions, counterclaims or setoffs whatsoever.  If the Commencement Date
should occur on a day other than the first day of a calendar month, or the
Expiration Date should occur on a day other than the last day of a calendar
month, then the monthly installment of Annual Base Rental for such fractional
month shall be prorated upon a daily basis based upon a thirty (30) day month.
Tenant shall have the right to audit all operating expense and real estate tax
reports once per year.  All such statements shall be prepared in accordance with
GAAP.  If such reports are over-stated by five percent or more, Landlord shall
be responsible for the cost of the audit and Tenant shall have the right to
conduct additional audits.

     3.2  Tenant shall pay to Landlord all charges and other amounts required
under this Lease and the same shall constitute additional rent hereunder (herein
called "Additional Rent"), including, without limitation, any sums due resulting
from the provisions of Articles 4 and 19 hereof.  All such amounts and charges
shall be payable to Landlord at the place where the Annual Base Rental is
payable.  Landlord shall have the same remedies for a default in the payment of
Additional Rent as for a default in the payment of Annual Base Rental.

     3.3  Tenant shall have a free rent period of three and one-half (3 1/2)
months beginning on the Commencement Date.

     4.  ADDITIONAL RENT FOR EXCESS OPERATING EXPENSES AND TAXES

     4.1  For purposes of this Article 4, the following terms shall have the
meanings hereinafter set forth;

          (a) "Tenant's Share of Excess Expenses" for any Expense Year (as
hereinafter defined) shall be calculated by multiplying the amount of Excess
Expenses (as hereinafter defined) by the fraction which is derived by dividing
the Rentable Area of the Premises by the Total Rentable Area of Building Office
Space.
<PAGE>
 
          (b) "Tenant's Share of Excess Taxes" for any Tax Year (as hereinafter
defined) shall be calculated by multiplying the amount of Excess Taxes (as
hereinafter defined) by the fraction which is derived by dividing the Rentable
Area of the Premises by the total Rentable Area of the Building.

          (c) "Tax Year" shall mean each twelve (12) consecutive month period
commencing January 1st of each year during the Term, provided that Landlord,
upon notice to Tenant, may change the Tax Year from time-to-time to any other
twelve (12) consecutive month period and, in the event of any such change,
Tenant's share of Excess Taxes (as hereinafter defined) shall be equitably
adjusted for the Tax Years involved in any such change.

          (d) "Real Estate Taxes" shall mean all taxes, assessments and charges
levied upon or with respect to the Building or any improvements, fixtures and
equipment of Landlord used in the operation thereof, or Landlord's interest in
the Building or such other property.  Real Estate Taxes shall include, without
limitation, all general real property taxes and general and special assessments,
charges, fees or assessments for all governmental services or purported benefits
to the Building, service payments in lieu of taxes, all business privilege
taxes, and any tax, fee or excise on the act of entering into this Lease or any
other lease of space in the Building, or on the use or occupancy of the Building
or any part thereof, or on the rent payable under any Lease or in connection
with the business of renting space under any lease or in connection with the
business of renting space in the Building, that are now or hereafter levied or
assessed against Landlord by the United States of America, the Commonwealth of
Pennsylvania, or any political subdivision, public corporation, district or
other political or public entity, and shall also include any other tax, fee or
other excise, however described, that may be levied or assessed as a substitute
for, or as an addition to, in whole or in part, any other Real Estate Taxes
(including, without limitation, any municipal income tax) and any license fees,
tax measured or imposed upon rents, or other tax or charge upon Landlord's
business of leasing the Building, whether or not now customary or in the
contemplation of the parties on the date of this Lease.  Real Estate Taxes shall
not include transfer, inheritance or capital stock taxes or income taxes
measured by the net income of Landlord from all sources, unless, due to a change
in the method of taxation or any of such taxes is levied or assessed against
Landlord as a substitute for, or as an addition to, in whole or in part, any
other tax that would otherwise constitute a Real Estate Tax.  Real Estate Taxes
shall also include reasonable legal fees, costs and disbursements incurred in
connection with proceedings to contest, determine or reduce Real Estate Taxes.
If Real Estate taxes are reduced for any reason (i.e., successful proceedings to
contest taxes, etc.), then the reduction should be passed on to Tenant.
Provided that no reduction shall result in an amount that would be less than the
Base Year amount.  However, in the event that Real Estate Taxes are replaced
with a tax on Tenant's income, operations or other element that may be described
as a Tenant based tax, then Landlord will reduce Tenant's rent by the taxed
amount even if such action shall reduce Tenant's share of Real Estate Taxes
below the Base Year amount.

          (e) "Excess Taxes" with respect to any Tax Year shall mean the amount,
if any, by which Real Estate Taxes for such Tax Year exceed the product obtained
by multiplying the number of square feet of Total Rentable Area of Building by
the Excess Taxes Base set forth in the Basic Lease Information.
<PAGE>
 
          (f) "Expense Year" shall mean each twelve (12) consecutive month
period commencing January 1st of each year during the Term, provided that
Landlord, upon notice to Tenant, may change the Expense Year from time-to-time
to any other twelve (12) consecutive month period, and, in the event of any such
change, Tenant's Share of Excess Expenses (as hereinafter defined) shall be
equitably adjusted for the Expense Years involved in any such change.

          (g) "Expenses" shall mean the total cost and expenses paid or incurred
by Landlord in connection with the management, operation, maintenance and repair
of the Total Rentable Area of Building Office space, including, without
limitation, (i) building supplies and equipment, the cost of air conditioning,
electricity, steam, water, sewer rental and charges, heating, mechanical,
ventilating and elevator systems. and all other utilities, and the cost of
supplies and equipment and maintenance and service contracts in connection
therewith, and all taxes on such utilities; (ii) the cost of repairs, general
maintenance, cleaning and janitorial services; (iii) the cost of fire, extended
coverage, boiler, machinery, sprinkler, public liability, property damage,
earthquake, flood and other insurance and bonds; (iv) wages, salaries and other
labor costs, including taxes, insurance, retirement, medical, workers'
compensation, and other employee benefits; (v) fees, charges and other costs,
including management fees, consulting fees, legal fees and accounting fees, of
all independent contractors engaged by Landlord or reasonably charged by
Landlord if Landlord performs management services; (vi) the cost of supplying,
maintaining and operating security systems and service for the Building; (vii)
the cost of supplying, replacing and cleaning employee uniforms; (viii) the cost
of any capital improvements made to the Building and substantially benefiting
the Total Rentable Area of Building Office Space after completion of
construction such capital improvements as a labor-saving device or to effect
other economics in the operation or maintenance of the Building, or made to the
Building after the date of this Lease, that are required under any governmental
law or regulation that was not applicable to the Building at the time that
permits for the construction thereof were obtained, such cost to be amortized
over such reasonable period as Landlord shall determine, together with interest
on the unamortized balance at the rate of fifteen percent (15%) per annum or
such higher rate as may have been paid by Landlord on funds borrowed for the
purpose of constructing such capital improvements; (ix) costs incurred in the
preparation of Landlord's Tax Statement (as defined hereafter) and Landlord's
Expense Statement (as defined hereafter); and (x) any other expenses of any
other kind whatsoever reasonably incurred in managing, operating, maintaining,
and repairing all or any part of the Total Rentable Area of Building Office
Space.  Notwithstanding the foregoing, "Expenses" shall not include above-
standard use of utilities by other tenants within the Building, costs associated
with renovation to the common areas of the Building, if any, necessary to bring
such areas into compliance with the Americans with Disabilities Act, 42 U.S.C.
(S) 1201 et. seq. ("ADA") and "capital expenditures" to the Building, as such
term may be defined by the United States tax code, or any court of competent
jurisdiction interpreting the same.

          The total cost and expenses paid or incurred by Landlord in connection
with the following items shall not be included as "Expenses":  (i) utilities
expenses which are separately metered for any individual tenant in the Building;
(ii) any expense for which Landlord in reimbursed by a specific tenant by reason
of a special agreement or requirement of the occupancy of the Building by such
tenant; (iii) expenses for services provided by Landlord for the exclusive
benefit of a given tenant or tenants for which Landlord is directly reimbursed
by such tenant or tenants; and (iv) costs incurred by Landlord in the leasing of
space in the
<PAGE>
 
Building or procuring now tenants.  For purposes of such calculations, expenses
shall be increased to what they would have been if the Total Rentable Area of
Building Office Space was ninety-five (95%) occupied and Landlord paid such
expenses during any period in which the Total Rentable Area of Building Office
Space is less than ninety-five percent (95%) occupied. Tenant shall have the
right to review a detailed breakdown of Expenses and Real Estate Taxes.

          (h) "Excess Expenses" with respect to any Expense Year shall mean the
amount, if any, by which Expenses for such Expense Year exceed the product
obtained by multiplying the number of square feet of Total Rentable Area of
Building Office Space by the Excess Expenses Base set forth in the Basic Lease
Information.

     4.2  Tenant shall pay to Landlord on account of Tenant's Share of Excess
Taxes and as Additional Rent one twelfth (1/12th) of the amount of Tenant's
Share of Excess Taxes for each Tax Year on or before the first day of each month
during such Tax Year, in advance, in an amount estimated by Landlord and billed
by Landlord to Tenant; provided that Landlord shall have the right initially to
determine such monthly estimates and to revise such estimates from time-to-time.
With reasonable promptness after Landlord has received the tax bills for any Tax
Year, Landlord shall furnish Tenant with a statement (herein called "Landlord's
Tax Statement") setting forth the amount of Real Estate Taxes for such Tax Year
and the amount of Tenant's Share of Excess Taxes, if any.  If the actual amount
of Tenant's Share of Excess Taxes for such Tax Year exceeds the estimated amount
of Tenant's Share of Excess Taxes paid by Tenant for such difference between the
amount paid by Tenant and the actual Tax Year and the amount of Tenant's Share
of actual amount of Tenant's Share of Excess Taxes estimated amount of Tenant's
Share of Excess Tax Year, then Tenant shall pay to Landlord the difference
between the amount of estimated Tenant's Share of Excess Taxes paid by Tenant
and the actual amount of Tenant's Share of Excess Taxes within thirty (30) days
after receipt of Landlord's Tax Statement, and if the total amount of estimated
Tenant's Share of Excess Taxes paid by Tenant for any such Tax Year shall exceed
the actual amount of Tenant's Share of Excess Taxes for such Tax Year, then such
excess shall be credited against the next installment of the estimated amount of
Tenant's Share of Excess Taxes due from Tenant to Landlord hereunder.

     4.3  Tenant shall pay to Landlord on account of Tenant's Share of Excess
Expenses and an Additional Rent one twelfth (1/12th) of the amount of Tenant's
Share of Excess Expenses for each Expense Year on or before the first day of
each month of such Expense Year, in advance, in an amount estimated by Landlord
and billed by Landlord to Tenant; provided that Landlord shall have the right
initially to determine such monthly estimates and to revise such estimates from
time-to-time.  With reasonable promptness after the expiration of each Expense
Year, Landlord shall furnish Tenant with a statement (herein called "Landlord's
Expense Statement"), certified by an officer of the managing agent of Landlord,
setting forth in reasonable detail the Expenses for the Expense Year, and the
amount of Tenant's Share of Excess Expenses, if any.  If the actual amount of
Tenant's Share of Excess Expenses for such Expense Year exceeds the estimated
amount of Tenant's Share of Excess Expenses paid by Tenant for such Expense
Year, then Tenant shall pay to Landlord the difference between the amount of
estimated Tenant's Share of Excess Expenses paid by Tenant and the actual Amount
of Tenant's Share of Excess Expenses within fifteen (15) days after the receipt
of Landlord's Expense Statement, and if the total amount of estimated Tenant's
Share of Excess
<PAGE>
 
Expenses paid by Tenant for any such Expense Year shall exceed the actual
amount of Tenant's Share of Excess Expenses for such Expense Year, then such
excess shall be credited against the next installment of the estimated amount
of Tenant's Share of Excess Expenses due from Tenant to Landlord hereunder.

     4.4  If the Commencement Date or Expiration Date of this Lease shall occur
on a date other than the beginning or end of a Tax Year or Expense Year, the
amount of Tenant's Share of Excess Taxes, if any, and the amount of Tenant's
Share of Excess Expenses, if any, for the Tax Year and the Expense Year in which
the Commencement Date or Expiration Date falls shall be in the proportion that
the number of days in such partial year in which the Commencement Date or
Expiration Date occurs bears to 365; provided, however, Landlord may, pending
the determination of the amount, if any, of Excess Taxes and Excess Expenses for
such partial Tax Year and Expense Year, furnish Tenant with statements of
estimated Excess Taxes, estimated Excess Expenses, and the amount of Tenant's
Share of each for such partial Tax Year and Expense Year.  Within fifteen (15)
days after receipt of such estimated statement, Tenant shall remit to Landlord,
as Additional Rent, the amount of Tenant's Share of such Excess Taxes and
Tenant's Share of such Excess Expenses.  After such Excess Taxes and such Excess
Expenses have been finally determined and Landlord's Tax Statement and
Landlord's Expense Statement have been furnished to Tenant pursuant to Sections
4.2 and 4.3 hereof, then, if there shall have been an underpayment of the amount
of either Tenant's Share of Excess Taxes or Tenant's Share of Excess Expenses,
Tenant shall remit the amount of such underpayment to Landlord within fifteen
(15) days of receipt of such statements, and, if there shall have been an
overpayment, Landlord shall remit the amount of any such overpayment to Tenant
within fifteen (15) days of the issuance of such statements.

     5.  TERMS OF PAYMENT

     5.1  Tenant shall pay to Landlord, within fifteen (15) days after delivery
by Landlord to Tenant of bills or statements therefor; (a) sums equal to all
expenditures made and monetary obligations incurred by Landlord including,
without limitation, expenditures made and obligations incurred for reasonable
counsel fees, in connection with the remedying by Landlord for Tenant's account
pursuant to the provisions of Article 20 hereof; (b) sums equal to all losses,
costs, liabilities, damages and expenses referred to in Article 20 hereof; (c)
sums equal to all expenditures made and monetary obligations incurred by
Landlord, including, without limitation, expenditures made and obligations
incurred for reasonable counsel fees, in collecting or attempting to collect the
Annual Base Rental, any Additional Rent or any other sum of money accruing under
this Lease or in enforcing or attempting to enforce any rights of Landlord under
this Lease or pursuant to law; and (d) all other sums of money (other than
Annual Base Rental and Additional Rent which are to be due and payable) accruing
from Tenant to Landlord under the provisions of this Lease.  Any sum of money
(other than Annual Base Rental) accruing from Tenant to Landlord pursuant to any
provision of this Lease, including, without limitation, the provisions of
Exhibit C attached hereto, whether prior to or after the Commencement Date, may,
at Landlord's option, be deemed Additional Rent.  All obligations of the Tenant
under this Lease, including without limitation the Tenant's obligations under
this Section 5.1, shall survive the expiration or sooner termination of the
Term.

     5.2  If Tenant shall fail to pay any Annual Base Rental or Additional Rent
after the date same in due and payable, such unpaid amounts shall be subject to
a late payment charge
<PAGE>
 
equal to two percent (2%) per month of such unpaid amounts (the "Default Rate")
in each instance to cover Landlord's additional administrative costs and cost
of funds resulting from Tenant's failure.  Such late payment charge shall be
paid to Landlord together with such unpaid amounts. Such late payment charge
shall not diminish or impair any other remedies available to Landlord.

     6.  CONSTRUCTION OF THE PREMISES

     6.1  Prior to the Commencement Date, Tenant will perform the work and make
the installations in the Premises substantially as set forth as Building
Standard Work in Exhibit C annexed hereto and made a part hereof (such work and
installations being herein called "Tenant's Work").  Tenant, through the
services of LV Construction Corporation, whom the Landlord approves, shall, when
construction progress so permits, notify Landlord in advance of the approximate
date on which Tenant's Work will be substantially completed in accordance with
Exhibit C and will notify Landlord when Tenant's Work is in fact so completed.
Commencement of Tenant's Work shall constitute delivery of possession of the
Premises to Tenant and notice to Tenant of the Commencement Date pursuant to
construction of the Building or the Premises shall not affect or change this
Lease or invalidate same.  It is agreed that by occupying the Premises, Tenant
formally accepts same and acknowledges that the Premises are in the condition
called for hereunder.  Failure of Landlord to deliver possession of the Premises
within the time and in the condition provided for in this Lease will not give
rise to any claim for damages by Tenant against Landlord or Landlord's
contractor.  Landlord shall disburse to Tenant an Allowance ("Tenant's
Allowance") of $15 per square foot of Rentable Area based upon invoices
received.  Payment shall be made within fifteen (15) days of receipt.  Any final
balance will be paid thirty (30) days after construction has been completed
(including punch list items) and after the parties approve of the construction
finish.  In the event Tenant incurs less than $15.00 per square foot, Landlord
shall credit the balance to Tenant in the form of rent credits.

     7.  COMMON AREA MAINTENANCE

     7.1  The manner in which the common areas are maintained and operated and
the expenditures therefor shall be in accordance with Class A suburban office
buildings in the Pittsburgh, Pennsylvania area, and the use of such areas and
facilities shall be subject to such reasonable rules and regulations as Landlord
shall make from time-to-time.  The term "common areas' an used herein shall mean
the pedestrian sidewalks, hallways, lobby, corridors, delivery areas, elevators
and stairs not contained in the leased areas, public bathrooms and all other
areas or improvements that may be provided by Landlord for the convenience and
use of the tenants of the Building and their respective sub-tenants, agents,
employees, customers, invitees and any other licensees of Landlord.

     7.2  The purpose of attached Exhibit A is to show the location of the
Premises in the Building and Landlord hereby reserves the right, at any time and
from time-to-time, to make alterations or additions to the Building and the
common areas.  Landlord also reserves the right at any time and from time-to-
time to construct other improvements in the Building (including within the
common areas) and to enlarge same and make alterations therein or additions
thereto.
<PAGE>
 
     8.  CONDUCT OF BUSINESS BY TENANT

     8.1  Tenant shall use and occupy the Premises during the Term of this Lease
solely for the uses specified in the Basic Lease Information and for no other
use or uses without the prior written consent of Landlord.

     8.2  Tenant and all sublessees or assignees of Tenant shall not use or
occupy, or permit the use or occupancy of, the Premises or any part thereof for
any use other than the sole uses specifically set forth in the Basic Lease
Information or in any illegal manner, or in any manner that, in Landlord's
judgment, would adversely affect or interfere with any services required to be
furnished by Landlord to Tenant or to any other tenant or occupant of the
Building, or with the proper and economical rendition of any such service, or
with the use or enjoyment of any part of the Building by any other tenant or
occupant.

     9.  ALTERATIONS AND TENANT'S PROPERTY

     9.1  Tenant shall not make or permit any additions or alterations to the
mechanical, plumbing, HVAC or electrical systems in the Building and shall not
make or permit any alterations which affect the Building, installations,
additions or improvements, structural or otherwise (herein collectively called
"Alterations"), in or to the Premises without Landlord's prior written consent.
All Alterations permitted by Landlord and made by or on behalf of Tenant or any
person claiming through or under Tenant shall be made and performed (a) at
Tenant's cost and expense and at such time and in such manner as Landlord may
designate, (b) by contractors or mechanics approved by Landlord, (c) so that
same shall be at least equal in quality, value, and utility to the original work
or installation, (d) in accordance with the Rules and Regulations for the
Building adopted by Landlord from time-to-time and in accordance with all
applicable laws and regulations of governmental authorities having jurisdiction
over the Premises, (e) pursuant to plans, drawings and specifications which have
been reviewed and approved by Landlord prior to the commencement of the
Alterations, and (f) subject to all other terms and conditions of this Lease
including but not limited to Article 11.

     9.2  All appurtenances, fixtures, improvements, additions and other
property attached to or installed in the Premises by Landlord or on behalf of
Tenant, at Landlord's expense, shall be and remain the property of Landlord.
However, Landlord may require at Landlord's discretion the removal by Tenant of
property which has been attached to or installed in the Premises.  Tenant shall
pay to Landlord or its designees the cost of repairs of any damages to the
Premises or Building and/or losses caused by the removal of such property.  All
appurtenances, fixtures, improvements, additions and other property, whether
permanent or temporary, attached to or installed in the Premises by Tenant, at
Tenant's expense, or at the joint expense of Landlord and Tenant, shall be and
remain the property of Tenant, except if located above the ceiling or below the
floor, as long as Tenant removes the property without damage to the Building or
the Premises.

     9.3  Any furnishings and personal property placed in the Premises that are
removable without damage to the Building or the Premises, whether the property
of Tenant or leased by Tenant, are herein called "Tenant's Property".  Any
replacements of any property of Landlord, whether made at Tenant's expense or
otherwise, shall be and remain the property of Landlord.  Any of Tenant's
Property remaining on the Premises at the expiration of the Term shall be
<PAGE>
 
removed by Tenant at Tenant's cost and expense, and Tenant shall, at its cost
and expense, repair any damage to the Premises or the Building caused by such
removal.  Any of Tenant's Property not removed from the Premises prior to the
Expiration Date shall, after written notice to Tenant to remove Tenant's
Property and  Tenant's failure thereafter to remove same within ten (10) days,
at Landlord's option, become the property of Landlord or Landlord may remove
such Tenant's Property, and Tenant shall pay to Landlord Landlord's cost of
removal and of any repairs in connection therewith within ten (10) days after
Tenant's receipt of a bill therefor.  Tenant's obligation to pay any such costs
shall survive any termination of this Lease.

     10.  REPAIRS

     10.1  Tenant shall take good care of the Premises and, at Tenant's cost and
expense, shall make all repairs and replacements, as and when Landlord deems
reasonably necessary, to preserve the Premises in good working order and in a
clean, safe and sanitary condition.  Landlord shall not be liable for and,
except as provided in Article 15 hereof, there shall be no abatement of Annual
Base Rental with respect to any injury to or interference with Tenant's business
arising from any repairs, maintenance, alteration or improvement in or to any
portion of the Building, including the Premises, or in or to the fixtures,
appurtenances and equipment therein.

     10.2  All repairs and replacements made by or on behalf of Tenant or any
person claiming through or under Tenant shall be made and performed (a) at
Tenant's cost and expense and at such time and in such manner as Landlord may
designate, (b) by contractors or mechanics approved by Landlord, (c) so that
same shall be at least equal in quality, value, and utility to the original work
or installation, (d) in accordance with the Rules and Regulations for the
Building adopted by Landlord from time-to-time and in accordance with all
applicable laws and regulations of governmental authorities having jurisdiction
over the Premises, (e) pursuant to plans, drawings and specifications which have
been reviewed and approved by Landlord prior to the commencement of the repairs
or replacements and subject to all other terms and conditions of this Lease,
including, but not limited to, Article 11.  If Landlord gives Tenant notice of
the necessity of any repairs or replacements required to be made under Section
10.1 and Tenant fails to commence diligently to effect the same within ten (10)
days thereafter, Landlord may proceed to make such repairs or replacements and
the expenses incurred by Landlord in connection therewith shall be due and
payable from Tenant upon demand as Additional Rent; provided, that Landlord's
making any such repairs or replacements shall not be deemed a waiver of Tenant's
default in failing to make the same.  In addition, should Landlord determine
that emergency repairs or replacements of the Premises are necessitated, then
Landlord may proceed to make such repairs or replacements without prior notice
to the Tenant and the reasonable expenses incurred by Landlord in connection
therewith shall be due and payable from Tenant upon demand as Additional Rent.

     11.  LIENS

     11.1  Tenant shall keep the Premises and Building free from any liens
arising out of any work performed, material furnished or obligations incurred by
or for Tenant or any person or entity claiming through or under Tenant.  Prior
to Tenant performing any construction or other work on or about the Premises for
which a lien could be filed against the Premises or the Building, Tenant shall
enter into a written "no lien' agreement with the contractor who is to
<PAGE>
 
perform such work, and such agreement shall be filed and recorded in accordance
with the Mechanics' Lien Law of Pennsylvania, prior to the commencement of such
work. Notwithstanding the foregoing, if any mechanics' or other lien shall be
filed against the Premises or the Building purporting to be for labor or
material furnished or to be furnished at the request of the Tenant, then Tenant
shall at its expense cause such lien to be discharged of record by payment,
bond or otherwise, within ten (10) days after the filing thereof.  If Tenant
shall fail to cause such lien to be discharged of record within such ten-day
period, in addition to any other remedy available to it for such a default,
Landlord may cause such lien to be discharged by payment, bond or otherwise,
without investigation as to the validity thereof or as to any offsets or
defenses thereto, and Tenant shall, upon demand, reimburse Landlord for all
amounts paid and costs incurred including attorneys' fees, in having such lien
discharged of record.

     12.  COMPLIANCE WITH LAWS AND INSURANCE REQUIREMENTS

     12.1  Tenant, at Tenant's cost and expense, shall comply with all laws,
orders and regulations of federal, state, county and municipal authorities, and
with all directions, pursuant to law, of all public officers, that shall impose
any duty upon Landlord or Tenant with respect to the Premises or the use or
occupancy thereof, except that Tenant shall not be required to make any
structural Alterations in order to comply unless such Alterations shall be
necessitated or occasioned, in whole or in part, by the acts, omissions or
negligence of Tenant or any person claiming through or under Tenant, or any of
their servants, employees, contractors, agents, visitors or licensees, or by the
use or occupancy or manner of use or occupancy of the Premises by Tenant or any
such person.  Any work or installations made or performed by or on behalf of
Tenant or any person claiming through or under Tenant pursuant to the provisions
of this Article shall be made in conformity with, and subject to the provisions
of, Sections 9.1 and 10.2 and Article 11 hereof.

     12.2  Tenant shall not do anything, or permit anything to be done in or
about the Premises which shall (a) invalidate or be in conflict with the
provisions of any fire or other insurance policies covering the Building or any
property or any property located therein, or (b) result in a refusal by fire
insurance companies of good standing to insure the Building or any such property
in amounts required by Landlord's Mortgage (as hereinafter defined) or
reasonably satisfactory to Landlord, or (c) subject Landlord to any liability or
responsibility for injury to any person or property by reason of any business
operation being conducted in the Premises, or (d) cause any increase in the fire
insurance rates applicable to the Building or property located therein at the
beginning of the Term or at any time thereafter.  Landlord shall carry "All
Risk" Insurance at replacement value for the Building.  Said policy shall name
Tenant as an additional insured.  For the purpose of this Article, the term
"insurance" shall include, without limitation, Fire, Extended Coverage,
Vandalism and Malicious Mischief, Boiler, Rent and Business Interruption,
Liability and Sprinkler Leakage, all of which shall be provided for the Building
by Landlord in reasonable amounts.  Landlord covenants to use its best efforts
to keep such insurance premiums as low as reasonably possible, giving allowance
to the protection of Landlord and Tenant contemplated under this Lease.

     13.  SUBORDINATION
<PAGE>
 
     13.1  Without the necessity of any additional document being executed by
Tenant for the purpose of effecting a subordination, Tenant agrees that this
Lease and Tenant's tenancy hereunder are and shall be automatically subject and
subordinate at all times to (a) the lien of a first mortgage that may now exist
or hereafter be executed in any amount for which the Building, or Landlord's
interest or estate in any of said items is specified as security; and (b)
renewals, modifications, consolidations, replacements, and extensions of any of
the foregoing.  Notwithstanding the foregoing, Landlord and the holder of such
first mortgage lien on the Building (the "Landlord's Mortgagee") shall have the
right to partially subordinate or cause to be subordinated such lien to this
Lease and Tenant agrees to promptly execute the form of agreement set forth in
Exhibit D upon request of Landlord's Mortgagee.  In the event that any such
first mortgage is foreclosed or a conveyance in lieu of foreclosure is made for
any reason, Tenant shall, at the option of Landlord's Mortgagee or the grantee
or purchaser in foreclosure, notwithstanding any subordination of any such lien
to this Lease, attorn to and become the Tenant of the successor in interest to
Landlord at the option of such successor in interest.  Tenant covenants and
agrees to execute and deliver, upon demand by Landlord, Landlord's Mortgagee, or
by Landlord's successor in interest and in the form requested by Landlord,
Landlord's Mortgagee, or by Landlord's successor in interest, any additional
documents evidencing the priority or subordination of this Lease with respect to
the lien of any such first mortgage including a Subordination, Non-Disturbance
and Attachment Agreement satisfactory to Landlord, Landlord's Mortgagee, and
Landlord's successors in interest.

     14.  INABILITY TO PERFORM

     14.1  If, by reason of the occurrence of any of the events of delay
specified in Section 31.16 hereof, Landlord is unable to furnish or is delayed
in furnishing any utility or service required to be furnished by Landlord under
the provision of Article 19 or of any other Article of this Lease or of any
collateral instrument, or is unable to perform or make or is delayed in
performing or making any installations, decorations, repairs, alterations,
additions or improvements, whether required to be performed or made under this
Lease or under any collateral instrument or is unable to fulfill or is delayed
in fulfilling any of Landlord's other obligations under this Lease or any
collateral instrument, no such inability or delay shall constitute an actual or
constructive eviction, in whole or in part, but shall entitle Tenant to an
abatement or diminution of Annual Base Rental for the portion of the Premises
rendered unusable.  However, the same shall not impose any liability upon
Landlord or its agents by reason of inconvenience or annoyance to Tenant or by
reason by injury to or interruption of Tenant's business, or otherwise.  If
Landlord's inability or delay in fulfilling its obligations, as described in
this Section, renders fifty percent (50%) or more of Tenant's space unusable by
Tenant for ninety (90) days or longer, then Tenant may terminate this Lease.

     15.  DESTRUCTION

     15.1  If the Premises shall be damaged by fire or other casualty insured
against by Landlord's insurance policy covering the Building, and if Tenant
shall give prompt notice to Landlord of such damage, Landlord, at Landlord's
expense, shall repair such damage; provided, however, that Landlord shall have
no obligation to repair any damage to or to replace Tenant's Property,
Alterations or any other property or effects of Tenant.  Except an otherwise
provided in this Article 15, if the entire Premises shall be rendered
untenantable by reason of any such damage, the Annual Base Rental and Additional
Rent shall abate for the period from
<PAGE>
 
the date of such damage to the date when such damage to the Premises shall have
been repaired, and if only a part of the Premises shall be rendered
untenantable, the Annual Base Rental and Additional Rent shall abate for such
period in the proportion that the portion of the Rentable Area of the Premises
so rendered untenantable bears to the total Rentable Area of the Premises;
provided, however, if, prior to the date when all of such damage shall have
been repaired, any part of the Premises so damaged shall be rendered tenantable
or shall be used or occupied by Tenant or any person or persons claiming
through or under Tenant, then the amount by which the Annual Base Rental and
Additional Rent shall abate shall be equitably apportioned for the period from
the date of such use or occupancy to the date when all such damage shall have
been repaired.

     15.2  Notwithstanding the provisions of Section 15.1 hereof, if, prior to
or during the Term (a) the Premises shall be so damaged by fire or other
casualty that, in Landlord's opinion, substantial alteration, demolition or
restoration of the Premises shall be required, or (b) the Building shall be so
damaged by fire or other casualty that, in Landlord's opinion, substantial
alteration, demolition or reconstruction of the Building shall be required
(whether or not the Premises shall have been damaged or rendered untenantable),
then, in any of such events, either party at their option, and with the written
consent of Landlord's Mortgagee, may give to the other party, within ninety (90)
days after such fire or other casualty, a thirty (30) days' notice of Expiration
Date of this Lease and, in the event such notice is given, this Lease and the
Term shall terminate upon the expiration of such thirty (30) days with the same
effect as if the date of expiration of such thirty (30) days were the Expiration
Date; and the Annual Base Rental and Additional Rent shall be apportioned as of
such date and any prepaid portion of Annual Base Rental or Additional Rent for
any period after such date shall be refunded by Landlord to Tenant.  Tenant
shall be entitled to an abatement of Rent for the portion of Premises rendered
unusable during the thirty (30) day notice period.

     15.3  Landlord shall attempt to obtain and maintain, throughout the Term,
in Landlord's casualty insurance policies, provisions to the effect that such
policies shall not be invalidated should the insured waive, in writing, prior to
loss, any or all right of recovery against any party for loss occurring to the
Building.  In the event that at any time Landlord's casualty insurance carriers
shall exact an additional premium for the inclusion of such or similar
provisions, Landlord shall give Tenant notice thereof.  In such event, if Tenant
agrees, in writing, to reimburse Landlord for such additional premium for the
remainder of the Term, Landlord shall require the inclusion of such or similar
provisions by Landlord's casualty insurance carriers.  As long as such or
similar provisions are included in and to the extent that such a waiver is
permitted under Landlord's casualty insurance policies then in force, Landlord
hereby waives any right of recovery against Tenant, any other permitted occupant
of the Premises, and any of their servants, employees, or agents, for any lose
or damage to property occasioned by fire or other casualty that is an insured
risk under such policies.  In the event that at any time Landlord's casualty
insurance carriers shall not permit such waivers in Landlord's casualty
insurance policies, the waivers set forth in the foregoing sentence shall be
deemed of no further force or effect.

     15.4  Landlord or Tenant, acting for itself or for anyone claiming through
or under either Landlord or Tenant by way of subrogation or otherwise, hereby
waives any right of recovery against the other party for any loss or damage to
the Premises, Tenant's Property, Landlord's Property, or other property.
<PAGE>
 
     15.5  Nothing contained in this Lease shall relieve Landlord or Tenant of
any liability to the other party or to its insurance carriers which Landlord or
Tenant may have under law or under the provisions of this Lease in connection
with any damage to the Premises or the Building by fire or other casualty.

     15.6  Notwithstanding the provisions of this Article 15, if any such damage
is due to the fault or neglect of Tenant, any person claiming through or under
Tenant, or any of their servants, employees, agents, contractors, visitors or
licensees, then there shall be no abatement of Annual Base Rental or Additional
Rent; an election by Landlord to carry rental interruption insurance shall in no
way affect the provisions of this Article 15 or a lack of rental abatement in
such a case.

     16.  EMINENT DOMAIN

     16.1  If all of the Premises are condemned or taken in any manner for
public or quasi-public use, including, but not limited to, a conveyance or
assignment in lieu of a condemnation or taking, this Lease shall automatically
terminate as of the earlier of the date of the vesting of title or the date of
dispossession of Tenant as a result of such condemnation or other taking.  If a
part of the Premises is so condemned or taken, this Lease shall automatically
terminate as to the portion of the Premises so taken as of the earlier of the
date of the vesting of title or the date of dispossession of Tenant as a result
of such condemnation or taking.  If such portion of the Building is condemned or
otherwise taken so as to require, in the opinion of Landlord, a substantial
alteration or reconstruction of the remaining portions thereof, then this Lease
may be terminated by Landlord, as of the earlier of (a) the date of the vesting
of title, or the date of dispossession as a result of such condemnation or
taking, or (b) by written notice from Landlord to Tenant that the termination
shall occur on the sixtieth (60th) day following Landlord's receipt of notice of
the date on which said vesting or dispossession will occur.  Tenant shall have
the right to terminate this Lease if a part of the Premises is condemned or
taken in any manner for public or quasi-public use, including, but not limited
to, a conveyance or assignment in lieu of a condemnation or taking.

     16.2  This Lease shall not be affected if the taking authority by the
exercise of its power of eminent domain shall take the use or occupancy of the
Premises or any part thereof for a temporary period (hereinafter, "Temporary
Taking").  A Temporary Taking is a period of less than thirty (30) days.  The
Tenant shall continue to pay, in the manner and at the times specified in this
Lease, the full amount of Annual Base, Additional Rent and other charges payable
by the Tenant under this Lease.  Except only to the extent that the Tenant may
be prevented from so doing pursuant to the terms of the order of the taking
authority, Tenant shall continue to perform and observe all its other
obligations under this Lease, as though the Temporary Taking had not occurred.
Tenant shall be entitled to receive the entire Amount of any award made for the
"Temporary Taking" whether paid by way of damages, rent, or otherwise, unless
the period of temporary use or occupancy shall extend to or beyond the
Expiration Date of this Lease, in which case the award shall be apportioned
between Landlord and Tenant as of the Expiration Date, but Landlord shall in
that circumstance receive the entire portion of the award that is attributable
to physical damage to the Premises and the restoration thereof to the condition
immediately prior to the taking.  The Tenant covenants that, upon the
termination of any Temporary Taking, prior to the Expiration Date, it will, at
its sole cost and
<PAGE>
 
expense, restore the Premises, as nearly as may be reasonably possible, to the
condition in which the same ware immediately prior to the Temporary Taking.

     16.3  Except as provided in the preceding Section 16.2 Landlord shall be
entitled to the entire award in any condemnation proceeding or other proceeding
for taking for public or quasi-public use, including, without limitation, any
award made for the value of the leasehold estate created by this Lease.  No
award for any partial or entire taking shall be apportioned, and Tenant hereby
assigns to Landlord any award that may be made in such condemnation or other
taking, together with any and all rights of Tenant now or hereafter arising in
or to same or any part thereof; provided, however, that nothing contained herein
shall be deemed to give Landlord any interest in or to require Tenant to assign
to Landlord any award made to Tenant specifically for its relocation expenses or
the taking of personal property and fixtures belonging to Tenant; provided that
such award does not diminish or reduce the amount of the award payable to
Landlord.

     16.4  In the event of a partial condemnation or other taking that does not
result in a termination of this Lease as to the entire Premises, then the Annual
Base Rental shall be adjusted in proportion to the portion of the Premises taken
by such condemnation or other taking.

     17.  ASSIGNMENT

     17.1  Tenant shall not directly or indirectly, voluntarily or by operation
of law, sell, assign, encumber, pledge or otherwise transfer the Premises or
Tenant's leasehold estate hereunder (collectively, "Assignment"), without
Landlord's prior written consent in each instance.

     17.2  If Tenant desires at any time to enter into an Assignment of this
Lease, it shall first give written notice to Landlord of its desire to do so,
which notice shall contain (a) the name of the proposed assignee, (b) the nature
of the proposed assignee's business to be carried on in the Premises, (c) the
terms and provisions of the proposed Assignment including any sum(s) payable to
Tenant as consideration for entering into the Assignment, (d) such financial and
other information as Landlord may reasonably request concerning the proposed
assignee.

     17.3  At any time within thirty (30) days after Landlord's receipt of the
notice specified in Section 17.2 hereof, Landlord may by written notice to
Tenant elect to (a) take an Assignment of Tenant's leasehold estate specified in
Tenant's notice hereunder, (b) terminate this Lease, (c) consent to the
Assignment, or (d) disapprove the Assignment.  In the event Landlord elects to
take an Assignment from Tenant an described in subsection (a) above, the rent
payable by Landlord as tenant thereunder shall be the lower of that not forth in
Tenant's notice or the Annual Base Rental payable by Tenant under this Lease at
the time of the Assignment.  In the event Landlord elects the option not forth
in subsection (a) above, then Landlord shall have the right to use the Premises
for any legal purpose in its sole discretion and the right to further assign or
sublease the Premises without the consent of Tenant.  If Landlord consents to
the Assignment within said sixty (60) day period, Tenant may thereafter within
ninety (90) days, enter into such Assignment, upon the terms and conditions set
forth in the notice furnished by Tenant to Landlord pursuant to Section 17.2
hereof; provided, that if any sum is payable to Tenant in consideration of
Tenant's entering into such Assignment, then
<PAGE>
 
Tenant shall pay such sum to Landlord as Additional Rent prior to the execution
of the Assignment.  In addition, if any amounts are payable to Tenant as rent
under the Assignment, then Tenant shall pay to Landlord monthly during the term
of such Assignment as Additional Rent an amount equal to any amount by which
the total of all such rent payable to Tenant exceeds the monthly Annual Base
Rental as escalated then payable by Tenant under the Lease.

     17.4  No consent by Landlord to any Assignment by Tenant shall relieve
Tenant of any obligation to be performed by Tenant under this Lease, whether
arising before or after the Assignment.  The consent by Landlord to any
Assignment shall not relieve Tenant from the obligations to obtain Landlord's
express written consent to any other or subsequent Assignment.  Any Assignment
that is not in compliance with this Article 17 shall be void and, at the option
of Landlord, shall constitute a material default by Tenant under this Lease.
The acceptance of Annual Base Rental or Additional Rent by Landlord from a
proposed assignee shall not constitute the consent to such Assignment by
Landlord.

     17.5  Any sale or other transfer, including by consolidation, merger or
reorganization, of a majority of the voting stock of Tenant, if Tenant in a
corporation, or any sale or other transfer of a majority of the partnership
interests in Tenant, if Tenant is a partnership, shall be an Assignment for
purposes of this Article 17.  As used in this Section 17.5, the term "Tenant"
shall also mean any entity which has guaranteed Tenant's obligations under this
Lease, and the prohibition hereof shall be applicable to any sales or transfers
of the stock or partnership interests of said guarantor.

     17.6  Each assignee shall assume, as provided in this Section 17.6, all
obligations of Tenant under this Lease and shall be and remain liable jointly
and severally with Tenant for the payment of Annual Base Rental and Additional
Rent, and for the performance of all the terms, covenants, conditions and
agreements herein contained on Tenant's part to be performed for the Term.  No
Assignment otherwise permitted hereunder shall be binding on Landlord unless the
assignee or Tenant shall deliver to Landlord within ten (10) days of execution a
counterpart of the Assignment and an instrument in recordable form that contains
a covenant of assumption by the assignee satisfactory in substance and form to
Landlord, consistent with the requirements of this Section 17.6, but the failure
or refusal of the assignee to execute such instrument of assumption shall not
release or discharge the assignee from its liability an set forth above.

     17.7  In no event shall this Lease be assigned or assignable by operation
of law or by voluntary or involuntary bankruptcy proceedings or otherwise, and
in no event shall this Lease or any rights or privileges hereunder be an asset
of Tenant under any bankruptcy, insolvency, reorganization or other debtor
relief proceedings.

     17.8  Anything contained in the foregoing provisions of this Article 17 to
the contrary notwithstanding, neither Tenant nor any other person having an
interest in the possession, use, occupancy or utilization of space in the
Premises shall enter into any lease, sublease, license, concession or other
agreement for use, occupancy or utilization of space on the Premises which
provides for rental or other payment for such use, occupancy or utilization
based, in whole or in part, on the net income or profits derived by any person
from the premises leased, used, occupied or utilized, and any such purported
lease, sublease, license, concession or
<PAGE>
 
other agreement shall be absolutely void and ineffective as a conveyance of any
right or interest in the possession, use, occupancy or utilization of any part
of the Premises.

     18.  SUBLETTING

     18.1  Tenant shall not directly or indirectly, permit the Premises to be
occupied by anyone other than Tenant or sublet the Premises (collectively,
"Sublease") or any portion thereof without Landlord's prior written consent in
each instance.

     18.2  If Tenant desires at any time to enter into a Sublease of the
Premises or any portion thereof, it shall first give written notice to Landlord
of its desire to do so, which notice shall contain (a) the name of the proposed
subtenant or occupant, (b) the nature of the proposed subtenant's or occupant's
business to be carried on in the Premises, (c) the portion(s) of the Premises to
be subject to Sublease and the square feet thereof and the other terms and
provisions of the proposed Sublease including any sum(s) payable to Tenant an
consideration for entering into the Sublease, and (d) such financial and other
information as Landlord may reasonably request concerning the proposed subtenant
or occupant.

     18.3  At any time within sixty (60) days after Landlord's receipt of the
notice specified in Section 18.2 hereof, Landlord may by written notice to
Tenant elect to (a) Sublease itself the portion of the Premises specified in
Tenant's notice or any portion thereof, (b) terminate this Lease as to the
portion of the Premises that is specified in Tenant's notice or any portion
thereof, with a proportionate abatement in the Annual Base Rental, (c) consent
to the Sublease, or (d) withhold consent to the Sublease.  In the event Landlord
elects to sublease from Tenant as described in subsection (a) above, the subrent
payable by Landlord to Tenant shall be the lower of that set forth in Tenant's
notice or the Annual Base Rental payable by Tenant under this Lease at the time
of the Sublease (or a proportionate amount thereof representing the portion of
the Premises subject to the Sublease if less than the entire Premises is subject
to the Sublease).  In the event Landlord elects the option set forth in
subsection (a) above with respect to a portion of the Premises, then (i) Tenant
shall at all times provide reasonable and appropriate access to such portion of
the Premises and use of any common facilities, and (ii) Landlord shall have the
right to use such portion of the Premises for any legal purpose in its sole
discretion and the right to further sublease the portion of the Premises subject
to Landlord's election without the consent of Tenant.  If Landlord consents to
the Sublease within said sixty (60) day period, Tenant may thereafter within
ninety (90) days, enter into such Sublease of the Premises or portion thereof,
upon the terms and conditions set forth in the notice furnished by Tenant to
Landlord pursuant to Section 18.2 hereof; provided, that if any sum is payable
to Tenant in consideration of Tenant's entering into such sublease, then Tenant
shall pay such sum to Landlord prior to the execution of the Sublease.  In
addition, if any amounts are payable to Tenant as subrent under the Sublease,
Tenant shall pay to Landlord monthly during the term of such Sublease on account
as Additional Rent the amount by which such monthly subrent exceeds the product
of (i) the monthly Annual Base Rental then payable by Tenant under the Lease,
and (ii) the fraction derived by dividing the square feet of the portion of the
Premises subject to the Sublease by the Total Rentable Area of the Premises.

     18.4  No consent by Landlord to any Sublease by Tenant shall relieve Tenant
of any obligation to be performed by Tenant under this Lease, whether arising
before or after the Sublease.  The consent by Landlord to any Sublease shall not
relieve Tenant from the obligation to obtain Landlord's express written consent
to any other or subsequent Sublease.
<PAGE>
 
Any Sublease that is not in compliance with this Article 18 shall be void and,
at the option of Landlord, shall constitute a material default by Tenant under
this Lease.  The acceptance of Annual Base Rental or Additional Rent by
Landlord from a proposed sublessee shall not constitute the consent to such
Sublease by Landlord.

     18.5  Each sublessee shall assume, as provided in this Section 18.5, all
obligations of Tenant under this Lease and shall be and remain liable jointly
and severally with Tenant for the payment of Annual Base Rental and Additional
Rent, and for the performance of all the terms, covenants, conditions and
agreements herein contained on Tenant's part to be performed for the Term.  No
Sublease otherwise permitted hereunder shall be binding on Landlord unless the
sublessee or Tenant shall deliver to Landlord within ten (10) days of execution
a counterpart of the Sublease and an instrument in recordable form that contains
a covenant of assumption by the sublessee satisfactory in substance and form to
Landlord, consistent with the requirements of this Section 18.5, but the failure
or refusal of the sublessee to execute such instrument of assumption shall not
release or discharge the sublessee from its liability as set forth above.

     18.6  Anything contained in the foregoing provisions of this section to the
contrary notwithstanding, neither Tenant nor any other person having an interest
in the possession, use, occupancy or utilization of space in the Premises shall
enter into any lease, sublease, license, concession or other agreement for use,
occupancy or utilization of space on the Premises which provides for rental or
other payment for such use, occupancy or utilization based, in whole or in part,
on the net income or profits derived by any person from the premises leased,
used, occupied or utilized and any such purported lease, sublease, license,
concession or other agreement shall be absolutely void and ineffective an a
conveyance of any right or interest in the possession, use, occupancy or
utilization of any part of the Premises.

     19.  UTILITIES

     19.1  As long as Tenant is not in default in the performance of its
obligations under this Lease, Landlord shall furnish to the Premises during the
period from 8:00 a.m. to 6:00 p.m., Monday through Friday, and from 9:00 a.m. to
1:00 p.m. on Saturdays, except for New Year's Day, Memorial Day, Independence
Day, Labor Day, Thanksgiving, Christmas and such other holidays as are generally
recognized in the Pittsburgh area and subject to rules and regulations from
time-to-time established by Landlord: (a) heating, air conditioning and
ventilation, (b) passenger elevator service, (c) electric current in amounts
required for normal lighting by building standard overhead fluorescent fixtures
and for normal fractional horsepower office machines, and (d) water for lavatory
and drinking purposes.  It is understood that such passenger elevator service,
electric current and water will be available twenty-four (24) hours a day,
subject to Sections 19.2, 19.3, 19.4 hereof.  Landlord shall provide janitorial
service five days per week generally consistent with that furnished in other
first-class office buildings in the central business district of Pittsburgh and
shall provide window washing as determined by Landlord.

     19.2  Landlord may impose reasonable charges and establish reasonable rules
and regulations for the use of any heating, air conditioning, ventilation or
electric current by Tenant at any time other than during the hours set forth in
Section 19.1, and for the usage of any additional or unusual janitorial services
required because of any nonbuilding standard improvements in the Premises, the
carelessness of Tenant, the nature of Tenant's business
<PAGE>
 
(including the operation of Tenant's business other than from 8:00 a.m. to 6:00
p.m., Monday through Friday and 9:00 a.m. to 1:00 p.m. on Saturdays) and the
removal of any refuse and rubbish from the Premises except for discarded
material placed in wastepaper baskets and left for emptying as an incident to
Landlord's normal cleaning of the Premises.  Landlord shall not be required to
provide janitorial services for portions of the Premises used for preparing or
consuming food or beverages, for storage or as a mail room or storage room or
for similar purposes or as a lavatory other than the lavatory rooms shown an
Exhibit A attached hereto.

     19.3  Landlord shall not be liable for any interruption in or failure to
furnish any services or utilities when such interruption or failure is caused by
acts of God, accidents, breakage, repairs, strikes, lockouts, other labor
disputes, the making of repairs, alterations or improvements to the Premises or
the Building, the inability to obtain an adequate supply of fuel, steam, water,
electricity, labor or other supplies, any event included in Section 31.6, or by
any other condition beyond Landlord's reasonable control, including, without
limitation, any governmental energy conservation program, and Tenant shall not
be entitled to any damages resulting from such failure nor shall such failure
relieve Tenant of the obligation to pay the Annual Base Rental and Additional
Rent reserved hereunder or constitute or be construed as a constructive or other
eviction of Tenant unless the damages are due to the gross negligence or wilful
misconduct by Landlord, its agents or its employees.  In the event any
governmental entity promulgates or revises any statute, ordinance or building,
fire or other code or imposes mandatory or voluntary controls or guidelines on
Landlord or the Building or any part thereof, relating to the use or
conservation of energy, water, gas, light or electricity or the reduction of
automobile or other emissions or the provision of any other utility or service
provided with respect to this Lease or in the event Landlord is required or
elects to make alterations to any part of the Building in order to comply with
such mandatory or voluntary controls or guidelines, Landlord may, in its sole
discretion, comply with such mandatory or voluntary controls or guidelines or
make such alterations to the Building.  Such compliance and the making of such
alterations shall in no event entitle Tenant to any damages, relieve Tenant of
the obligation to pay the full Annual Base Rental and Additional Rent reserved
hereunder or constitute or be construed as a constructive or other eviction of
Tenant.

     19.4  Without the prior written consent of Landlord, which Landlord may
refuse in its sole discretion, Tenant shall not use any apparatus or device in
the Premises, including, without limitation, electronic data processing
machines, punch card machines and machines using, in the aggregate, current in
excess of 3 watts per square foot in area within the Premises (current in excess
of 3 watts per square foot of the Premises hereinafter called "Excessive
Current") or that will in any way increase the amount of electricity or water
usually furnished or supplied for use of the Premises as general office space;
nor connect any apparatus, machine or device with water pipes or electric
current (except through existing electrical outlets in the Premises), for the
purpose of using electric current or water.  If Tenant shall utilize such
Excessive Current, Landlord shall have the right to install an electric current
meter in the Premises to measure the unit of electric current consumed on the
Premises.  The cost of any such meter and separate conduit, wiring or panel
requirements and the installation, maintenance and repair thereof shall be paid
for by Tenant, and Tenant agrees to reimburse Landlord promptly upon demand
therefor by Landlord for all such Excessive Current as shown by said meter, at
the rates charged for such services by the local public utility furnishing the
same, plus any additional expense incurred in keeping the account of the
electric current so consumed.  If the temperature otherwise maintained in any
portion of the Premises by the heating, air
<PAGE>
 
conditioning or ventilation systems is affected as a result of (a) any lights,
machines or equipment (including without limitation electronic data processing
machines) used by Tenant in the Premises, (b) the occupancy of the Premises by
more than one person per one hundred seventy-five (175) square feet of rentable
area therein, or (c) an aggregate electrical load in excess of three (3) watts
per square foot in any room or area of the Premises, Landlord shall have the
right to install any machinery and equipment that Landlord reasonably deems
necessary to restore temperature balance, including, without limitation,
modifications to the standard air conditioning equipment, and the cost thereof,
including the cost of installation and any additional coat of operation and
maintenance incurred thereby, shall be paid by Tenant to Landlord as Additional
Rent hereunder upon demand by Landlord.

     20.  DEFAULT

     20.1  Events of Default.  The occurrence of any of the following shall
constitute an Event of Default on the part of Tenant:

          (a) Nonpayment of Annual Base Rental or Additional Rent.  Failure to
pay any installment of Annual Base Rental or Additional Rent due and payable
hereunder, upon the date when said payment is due, such failure continuing for a
period of five (5) business days after the due date thereof.

          (b) Other Obligations.  Failure to perform any obligation, agreement
or covenant under this Lease other than those matters specified in subparagraph
(a) of this Section 20.1, such failure continuing for ten (10) business days
after written notice by Landlord to Tenant of such failure.

          (c) Abandonment.  Vacation or abandonment of the Premises for a
continuous period in excess of ten (10) business days.

          (d) Removal.  Any removal or attempted removal, without the prior
approval of Landlord, of any of Tenant's equipment, appliances, or personal
property from the Premises for any reason other than the normal and usual
operation of Tenant's business.
 
          (e) General Assignment.  A general assignment by Tenant or Tenant's
guarantor (if any) for the benefit of creditors.

          (f) Bankruptcy.  The filing of any voluntary petition in bankruptcy by
Tenant or Tenant's guarantor (if any), or the filing of an involuntary petition
by Tenant's creditors or any of guarantor's creditors, which involuntary
petition remains undischarged for a period of ten (10) business days;

          (g) Receivership.  The employment of a receiver to take possession of
substantially all of Tenant's assets or any guarantor's assets or the Premises,
if such receivership remains undissolved for a period of ten (10) business days
after creation thereof;

          (h) Attachment.  The attachment, execution or other judicial seizure
of all or substantially all of Tenant's assets or any guarantor's assets or the
Premises, if such attachment or other seizure remains undismissed or
undischarged for a period of ten (10) business days after the levy thereof;
<PAGE>
 
          (i) Insolvency.  The admission by Tenant or Tenant's guarantor (if
any) in writing of its inability to pay its debts as they become due, the filing
by Tenant or Tenant's guarantor (if any) of a petition seeking any
reorganization, arrangement, composition, readjustment, liquidation, dissolution
or similar relief under any present or future statute, law or regulation, the
filing by Tenant or Tenant's guarantor (if any) of an answer admitting or
failing timely to contest a material allegation of a petition filed against
Tenant or Tenant's guarantor (if any) in any such proceeding or, if within ten
(10) days after the commencement of any proceeding against Tenant or Tenant's
guarantor (if any) seeking any reorganization, or arrangement, composition,
readjustment, liquidation, dissolution or similar relief under any present or
future statute, law or regulation, such proceeding shall not have been
dismissed.

     20.2  Upon the occurrence of any Event of Default by Tenant which is not
cured by Tenant within the grace periods, if any, specified in Section 20.1
hereof, Landlord shall have the following rights and remedies, in addition to
all other rights or remedies available to Landlord in law or equity:

          (a) Landlord may cure or perform for the account of Tenant any such
matter or obligation in default by Tenant and Tenant shall immediately pay on
account as Additional Rent any expenditures made and the amount of any
obligations incurred in connection therewith, plus interest, from the date of
any such expenditure, at the Default Rate set forth in Section 5.2;

          (b) Landlord may accelerate all Annual Base Rental and Additional Rent
due for the balance of the Term of this Lease and declare the same to be
immediately due and payable.  In determining the amount of any future payments
payable to Landlord on account of Tenant's Share of Excess Taxes and Tenant's
Share of Excess Expenses, Landlord may make such determination based upon the
amount of Tenant's Share of Excess Expenses and Tenant's Share of Excess Taxes
paid or payable by Tenant for the full year immediately prior to such default;
 
          (c) Landlord, at its option, may serve notice upon Tenant that this
Lease and the then unexpired Term hereof shall cease and expire and terminate on
the date specified in such notice, to be not less than five (5) days after the
date of such notice without any right on the part of the Tenant to save the
forfeiture by payment of any sum due or by the performance of any term,
provision, covenant, agreement or condition broken; and, thereupon and at the
expiration of the time limit in such notice, this Lease and the Term hereof
granted, as well as the right, title and interest of the Tenant hereunder, shall
wholly cease and expire and terminate in the same manner and with the same force
and effect (except as to Tenant's liability) as if the date fixed in such notice
were the date herein granted for expiration of the Term of this Lease.
Thereupon, Tenant shall immediately quit and surrender to Landlord the Premises
by summary proceedings, detainer, ejectment or otherwise and remove all
occupants thereof and, at Landlord's option, any property thereon without being
liable to indictment, prosecution or damages therefor.  No such expiration or
termination of this Lease shall relieve Tenant of its liability and obligations
under this Lease, whether or not the Premises shall be relet.  Applicable
Landlord/Tenant statutes of the Commonwealth of Pennsylvania shall control as to
any rights or remedies of the parties not otherwise set forth herein.  As to any
conflict, the Lease shall be deemed controlling;
<PAGE>
 
          (d) Landlord may, at any time after the occurrence of any Event of
Default and after Landlord gives ten (10) days notice and an opportunity to
cure, re-enter and repossess the Premises and any part thereof and attempt in
its own name, as agent for Tenant, if this Lease not be terminated or in its own
behalf if this Lease be terminated, to relet all or any part of such Premises
for and upon such terms and to such person or firms or corporations and for such
period or periods as Landlord, in its sole discretion, shall determine,
including the term beyond the termination of this Lease; and Landlord shall not
be required to accept any tenant offered by Tenant or observe any instruction
given by Tenant about such reletting or do any act or exercise any care or
diligence with respect to such reletting or to the mitigation of damages.  For
the purpose of such reletting, Landlord may decorate or make repairs, changes,
alterations or additions in or to the Premises as may be reasonably required in
order for Landlord to relet the Premises, but not to exceed fifteen (15) dollars
per square foot without Tenant's consent, provided however, that if Tenant
delays or withholds consent, the Landlord shall be relieved of any duty to relet
the Premises; and the cost of such decoration, repairs, changes, alterations or
additions shall be charged to and be payable by Tenant as:  (a) Additional Rent
hereunder, or (b) in the event the Lease has been terminated, as damages.
Tenant shall also pay to Landlord any reasonable brokerage and legal fees
expended by Landlord.  Any sums collected by Landlord from any new tenant-
obtained on account of the Tenant shall be credited against the balance of the
Annual Base Rental and Additional Rent due hereunder as aforesaid.  Tenant shall
pay to Landlord monthly, on the days when the Annual Base Rental due would have
been payable under this Lease, the amount due hereunder less the amount obtained
by Landlord from such new tenant;

          (e) Landlord shall have the right of injunction, in the event of a
breach or threatened breach by Tenant of any of the agreements, conditions,
covenants or terms hereof, to restrain the same and the right to invoke any
remedy allowed by law or in equity, whether or not other remedies, indemnity or
reimbursements are herein provided.  The rights and remedies given to Landlord
in this Lease are distinct, separate and cumulative remedies; and no one of
them, whether or not exercised by Landlord, shall be deemed exclusive of any of
the others.

          (f) When this Lease shall be terminated by reason of the breach of any
provision hereof, either during the original Term of this Lease or any renewal
thereof, and also as soon as the Term hereby created or any renewal thereof
shall have expired, it shall be lawful for any attorney as attorney for Tenant
to file an agreement for entering in any court of competent jurisdiction an
amicable action and confession of judgment in ejectment against Tenant and all
persons claiming under Tenant for the recovery by Landlord of possession of the
Premises, for which this Lease or a true and correct copy thereof, shall be his
sufficient warrant; whereupon, if Landlord so desires, a writ of possession may
issue forthwith, without any prior writ or proceedings whatsoever, and provided
that if for any reason after such action shall have been commenced the same
shall be terminated and possession remain in or be restored to Tenant, Landlord
shall have the right upon any subsequent default or defaults, or upon the
termination of this Lease an hereinbefore set forth, to bring one or more
amicable action or actions as hereinbefore set forth to recover possession as
aforesaid.

     21.  INDEMNITY

     21.1  Except as provided in Article 21.2, Tenant agrees to indemnify
Landlord against and save Landlord harmless from any and all loss, cost,
liability, damage and expense
<PAGE>
 
including, without limitation, penalties, fines and reasonable counsel fees,
incurred in connection with or arising from any cause whatsoever in, on or
about the Premises, including, without limiting the generality of the foregoing
(a) any default by Tenant in the observance or performance of any of the terms,
covenants or conditions of this Lease on Tenant's part to be observed or
performed, or (b) the use or occupancy or manner of use or occupancy of the
Premises by Tenant or any person claiming through or under Tenant, or (c) the
condition of the Premises or any occurrence or happening on the Premises from
any cause whatsoever, or (d) any acts, omissions or negligence of Tenant or any
person claiming through or under Tenant, or of the contractors, agents,
servants, employees, visitors or licensees of Tenant or any such person, in, on
or about the Premises or the Building, either prior to, during, or after the
expiration of, the Term including, without limitation, any acts, omissions or
negligence in the making or performing of any Alterations. Tenant further
agrees to indemnify and save harmless Landlord, Landlord's agents, and the
lessor or lessors under all ground or underlying leases, from and against any
and all loss, cost, liability, damage and expense including, without
limitation, reasonable counsel fees, incurred in connection with or arising
from any claims by any persons by reason of injury to persons or damage to
property occasioned by any use, occupancy, condition, occurrence, happening,
act, omission or negligence referred to in the preceding sentence.

     21.2  Except as provided in Article 21.1, Landlord agrees to indemnify
Tenant against and save Tenant harmless from any loss, cost, liability, damage
and expense that is caused by the negligence of Landlord, its agents or its
employees.

     22.  TENANT'S INSURANCE

     22.1  Tenant shall procure at its cost and expense and keep in effect
during the Term (a) comprehensive general liability insurance including
contractual liability with a minimum combined single limit of liability of two
million dollars ($2,000,000); (b) reasonable and customary property insurance in
amounts sufficient to repair or replace Tenant's personal property and any
improvements or betterments in which the Tenant has an insurable property
interest; and (c) any other insurance reasonably required by Landlord.  Such
insurance shall name Landlord as an additional insured, shall specifically
include the liability assumed hereunder by Tenant (provided that the amount of
such insurance shall not be construed to limit the liability of Tenant
hereunder), and shall provide that Landlord shall receive thirty (30) days'
written notice from the insurer prior to any cancellation or change of coverage.
Tenant shall deliver policies of such insurance or certificates thereof to
Landlord on or before the Commencement Date, and thereafter at least thirty (30)
days before the expiration dates of expiring policies; and, in the event Tenant
shall fail to procure such insurance, or to deliver such policies or
certificates, Landlord may, at its option, procure same for the account of
Tenant, and the cost thereof shall be paid to Landlord an Additional Rent within
five (5) days after delivery to Tenant of bills therefor.  Tenant's compliance
with the provisions-of this Article 22 shall in no way limit Tenant's liability
under any of the other provisions of this Lease.

     22.2  Neither party hereto shall be liable to the other party hereunder nor
to any insurer or other party claiming by way of subrogation through or under
such other party with respect to any loss or damage to the extent that such
other party shall be reimbursed or has the right to be reimbursed out of
insurance (without regard to any deductible provision in any policy) carried for
such other party's protection with respect to such loss or damage.
<PAGE>
 
     23.  LIMITATION OF LANDLORD'S LIABILITY

     23.1  Landlord represents and warrants it will enforce the standards of the
Building on tenants in the Building.  However, Landlord shall not be responsible
for or liable to Tenant for any loss or damage that may be occasioned by or
through the acts or omissions of persons occupying adjoining premises or any
part of the premises adjacent to or connected with the Premises or any part of
the Building or for any loss or damage resulting to Tenant or its property from
burst, stopped or leaking water including sprinkler systems, gas or smoke, vapor
or other airborne contaminants, sewer or steam pipes or for any damage or loss
of property within the Premises from any causes whatsoever, including theft,
unless the same shall be the result of the negligence of Landlord, its agents or
it's employees.  Landlord shall provide reasonable assistance to Tenant pursuing
a claim against a third party as long as there is no cost to Landlord.
<PAGE>
 
     24.  ACCESS TO PREMISES

     24.1  Landlord reserves and shall at all times have the right to enter the
Premises at all reasonable times to inspect same, to supply any service to be
provided by Landlord to Tenant hereunder, to show the Premises to prospective
purchasers, mortgagees or tenants, and to alter, improve or repair the Premises
and any portion of the Building, without abatement of Annual Base Rental or
Additional Rent, and may for that purpose erect, use and maintain scaffolding,
pipes, conduits and other necessary structures in and through the Premises where
reasonably required by the character of the work to be performed, provided that
the entrance to the Premises shall not be blocked thereby, and further provided
that the business of Tenant shall not be interfered with unreasonably.  Landlord
reserves and shall at all times during the six (6) month period prior to the
expiration of the Lease to have the right to enter the Premises to show the
Premises to prospective purchasers, mortgagees or tenants.  Landlord shall also
at all times and after reasonable notice to Tenant, and written approval by
Tenant, have the right to enter the Premises to show third parties the Premises
for the purpose of letting other space in the Building.  Access to the Premises
by Landlord shall be front door access and Tenant is not required to provide
access to safes or vaults.  Tenant shall be entitled to a prorata abatement of
the rent if Landlord affirmatively or intentionally shuts down the Building, but
Tenant shall not be entitled to a prorata abatement if the Building is shut down
due to an act of God, an act of war or any other act not controlled by Landlord.
Tenant hereby waives any claim for damages for any injury or inconvenience to or
interference with Tenant's business, any loss of occupancy or quiet enjoyment of
the Premises or any other loss occasioned thereby.  For each of the aforesaid
purposes, Landlord shall at all times have and retain a key with which to unlock
all of the doors in, upon and about the Premises, excluding Tenant's vaults and
safes, or special security areas (designated in advance), and Landlord shall
have the right to use any and all means that Landlord may deem necessary or
proper to open said doors in an emergency, in order to obtain entry to any
portion of the Premises, and any entry to the Premises or portions thereof
obtained by Landlord by any of said means, or otherwise, shall not under any
circumstances be construed or deemed to be a forcible or unlawful entry into, or
a detainer of, the Premises, or an eviction, actual or constructive, of Tenant
from the unlawful entry into, or a detainer of, the Premises, or an eviction,
actual or constructive, of Tenant from the Premises or any portion thereof.
Landlord shall also have the right at any time, without same constituting an
actual or constructive eviction and without incurring any liability to Tenant
therefor, to change the arrangement and/or location of entrances or passageways,
doors and doorways, and corridors, elevators, stairs, toilets and other public
parts of the Building.

     25.  NOTICES

     25.1  Except as otherwise expressly provided in this Lease, any bills,
statements, notices, demands, requests or other communications given or required
to be given under this Lease shall be effective only if rendered or given in
writing, sent by registered or certified mail or delivered personally, (a) to
Tenant (i) at Tenant's address set forth in the Basic Lease Information, if sent
prior to Tenant's taking possession of the Premises, or (ii) at the Building if
sent subsequent to Tenant's taking possession of the Premises, or (iii) at any
place where Tenant or any agent or employee of Tenant may be found if sent
subsequent to Tenant's vacating, deserting, abandoning or surrendering the
Premises, or (b) to Landlord at Landlord's address set forth in the Basic Lease
Information, or (c) to such other address as either Landlord or Tenant may
designate as its new address for such purpose by notice given to the other in
<PAGE>
 
accordance with the provisions of this Section 25.1. Any such bill, statement,
notice, demand, request or other communication shall be deemed to have been
rendered or given two (2) business days after the date when it shall have been
mailed as provided in this Section 25.1 if sent by registered or certified mail,
or upon the date personal delivery is made.  If Tenant is notified of the
identity and address of: (i) the Landlord's Mortgagee, or (ii) the holder(s) of
any subordinate mortgage lien(s) on the Building ("Other Mortgagee(s)"), or
(iii) ground or other lessor ("Lessor(s)"), then Tenant shall give to such
Landlord's Mortgagee, Other Mortgagee(a), and Lessor(s) notice of any default by
Landlord under the terms of this Lease in writing sent by registered or
certified mail, and such Landlord's Mortgagee, Other Mortgagee(s), and Lessor(s)
shall be given a reasonable opportunity to cure such default prior to Tenant
exercising any remedy available to it.

     26.  NO WAIVER

     26.1  No failure by Landlord to insist upon the strict performance of any
obligation of Tenant under this Lease or to exercise any right, power or remedy
consequent upon a breach thereof, no acceptance of full or partial Annual Base
Rental or Additional Rent during the continuance of any such breach, and no
acceptance of the keys to or possession of the Premises prior to the termination
of the Term by any employee of Landlord shall constitute a waiver of any such
breach or of such term, covenant or condition or operate as a surrender of this
Lease.  No payment by Tenant or receipt by Landlord of a lesser amount than the
aggregate of all Annual Base Rental and Additional Rent then due under this
Lease shall be deemed to be other than on account of the first items of such
Annual Base Rental and Additional Rent then accruing or becoming due, unless
Landlord elects otherwise; and no endorsement or statement on any check and no
letter accompanying any check or other payment of Annual Base Rental or
Additional Rent in any such lesser amount and no acceptance of any such check or
other such payment by Landlord shall constitute an accord and satisfaction, and
Landlord may accept such check or payment without prejudice to Landlord's right
to recover the balance of such Annual Base Rental or Additional Rent or to
pursue any other legal remedy.

     27.  TENANT'S CERTIFICATES

     27.1  Tenant, at any time, and from time-to-time upon not less than ten
(10) days' prior written notice from Landlord, will execute, acknowledge and
deliver to Landlord and, at Landlord's request, to any prospective purchaser,
Lessor, or Landlord's Mortgagee, or other Mortgagee of any part of the Building,
a certificate of Tenant certifying: (a) that Tenant has accepted the Premises
(or, if Tenant has not done so, that Tenant has not accepted the Premises and
specifying the reasons therefor), (b) the Tenant has entered into possession of
the Premises (c) the Commencement and Expiration Dates of this Lease, (d) the
amount of Annual Base Rental payable under the Lease (e) that this Lease is the
entire agreement between the parties and is unmodified and in full force and
effect (or, if there have been modifications, that same is in full force and
effect as modified and stating the modifications), and has not been assigned (f)
whether or not there are then existing any defenses against the enforcement of
any of the obligations of Tenant under this Lease (and, if so, specifying same),
(g) whether or not there are then any defaults by Landlord in the performance of
its obligations under this Lease (and, if so, specifying same), (h) that Tenant
has received all required contributions from Landlord on account of Tenant's
improvements, (i) the dates, if any, to which
<PAGE>
 
the Annual Base Rental and Additional Rent and other charges under this Lease
have been paid and the amounts of said Annual Base Rental and Additional Rent,
and that no Annual Base Rental, Additional Rent, or security deposit has been
paid in advance of its due date, and (j) any other information that may
reasonably be required by any of such persons.  It is intended that any such
certificate of Tenant delivered pursuant to this Section 27.1 may be relied
upon by Landlord and any prospective purchaser, Lessor, Landlord's Mortgagee,
or other Mortgagee(s) of any part of the Building. Tenant's failure to deliver
such Certificate within said ten day period shall be a default hereunder and
shall be conclusive upon Tenant that this Lease is in full force and effect and
unmodified, and that there are no uncured defaults in Landlord's performance
hereunder.

     28.  RULES AND REGULATIONS

     28.1  Tenant shall faithfully observe and comply with the rules and
regulations attached to this Lease as Exhibit E and all modifications thereof
and additions thereto from time-to-time put into effect by Landlord.  Subject to
its obligations as set forth in Section 23 hereof, Landlord shall not be
responsible for the nonperformance by any other tenant or occupant of the
Building of any said rules and regulations.  In the event of an express and
direct conflict between the terms, covenants, agreements and conditions of this
Lease and the terms, covenants, agreements and conditions of such rules and
regulations, an modified and amended from time-to-time by Landlord, this Lease
shall control.

     29.  SECURITY DEPOSIT

          [This space left intentionally blank]



     30.  AUTHORITY

     30.1  If Landlord or Tenant signs as a corporation or a partnership, each
of the persons executing this Lease on behalf of either Landlord or Tenant does
hereby covenant and warrant that the party on whose behalf such person is
executing this Lease is a duly authorized and existing entity, that such party
has and is qualified to do business in Pennsylvania, has full right and
authority to enter into this Lease and that the persons signing on behalf of
Landlord or Tenant (as the case may be) are authorized to do so.  Upon either
party's request, the other party shall provide the requesting party with
evidence reasonably satisfactory to the requesting party confirming the
foregoing covenants and warranties.

     31.  MISCELLANEOUS

     31.1  The words "Landlord" and "Tenant" as used herein shall include the
plural as well as the singular.  The words used in neuter gender include the
masculine and feminine.  If there is more than one Tenant, the obligations under
this Lease imposed on Tenant shall be joint and several.  The captions preceding
the articles of this Lease have been inserted solely as a
<PAGE>
 
matter of convenience and such captions in no way define or limit the scope or
intent of any provision of this Lease.

     31.2  The terms, covenants and conditions contained in this Lease shall
bind and inure to the benefit of Landlord and Tenant and, except as otherwise
provided herein, their respective personal representatives, successors and
assigns; provided, however, upon the sale, assignment or transfer by the
Landlord named herein (or by any subsequent landlord) of its interest in the
Building, as owner or lessor, including any transfer by operation of law, the
Landlord (or any subsequent landlord) shall be relieved from all subsequent
obligations or liabilities under this Lease, and all obligations subsequent to
such sale, assignment or transfer (but not any obligations or liabilities that
have accrued prior to the date of such sale, assignment or transfer) shall be
binding upon the grantee, assignee or other transferee; any such grantee,
assignee, or other transferee shall, by accepting such interest, shall be deemed
to have assumed such subsequent obligations and liabilities.  Notwithstanding
anything to the contrary set forth herein, if Landlord's Mortgagee or Other
Mortgagee(s) shall succeed to Landlord's interests hereunder, then Landlord's
Mortgagee or Other Mortgagee(s) shall not be deemed to have assumed any
obligations or liabilities under this Lease which arose prior to the date any
such Mortgagee shall have requested Tenant to attorn to such Mortgagee.  A lease
of the entire Building to a person other than for occupancy thereof shall be
deemed a transfer within the meaning of this Section 31.2.

     31.3  If any provision of this Lease or the application thereof to any
person or circumstance shall, to any extent, be invalid or unenforceable, the
remainder of this Lease, or the application of such provision to persons or
circumstances other than those as to which it is invalid or unenforceable, shall
not be affected thereby, and each provision of this Lease shall be valid and
enforceable to the full extent permitted by law.

     31.4  This Lease and the rights and obligations of the parties hereunder
shall be construed and enforced in accordance with the laws of the Commonwealth
of Pennsylvania.

     31.5  Submission of this instrument for examination or signature by Tenant
does not constitute a reservation of or an option for lease, and it is not
effective as a lease or otherwise until execution and delivery by both Landlord
and Tenant.

     31.6  This instrument, including the Exhibits hereto, which are made a part
of this Lease, contains the entire agreement between the parties and all prior
negotiations and agreements are merged herein.  Neither Landlord nor Landlord's
agents have made any representations or warranties with respect to the Premises,
the Building or this Lease except as expressly set forth herein, and no rights,
easements or licenses are or shall be acquired by Tenant by implication or
otherwise unless expressly set forth herein.

     31.7  The review, approval, inspection or examination by Landlord of any
item to be reviewed, approved, inspected or examined by Landlord under the terms
of this Lease or the Exhibits attached hereto shall not constitute the
assumption of any responsibility by Landlord for either the accuracy or
sufficiency of any such item or the quality or suitability of such item for its
intended use.  Any such review approval, inspection or examination by Landlord
is for the sole purpose of protecting Landlord's interests in the Building and
under this Lease, and no third parties, including, without limitation, Tenant or
any person or entity claiming through or under
<PAGE>
 
Tenant, or the contractors, agents, servants, employees, visitors or licensees
of Tenant or any such person or entity, shall have rights hereunder.

     31.8  Upon the expiration or sooner termination of the Term, Tenant will
quietly and peacefully surrender to Landlord the Premises in the condition in
which they are required to be kept as provided in Article 9 hereof, ordinary
wear and tear excepted.  Tenant shall surrender the Premises to Landlord at the
end of the Term hereof, without-notice of any kind.

     31.9  Upon Tenant paying the Annual Base Rental and Additional Rent and
performing all of Tenant's obligations under this Lease, Tenant may peacefully
and quietly enjoy the Premises during the Term as against all persons or
entities lawfully claiming by or through Landlord; subject, however, to the
provisions of this Lease.

     31.10  Tenant covenants and agrees that no diminution of light, air or view
by any structure that may hereafter be erected (whether or not by Landlord)
shall entitle Tenant to any reduction of Annual Base Rental or Additional Rent
under this Lease, result in any liability of Landlord or Tenant, or in any other
way affect this Lease or Tenant's obligations hereunder.

     31.11  Any holding over after the expiration of the Term with the written
consent of Landlord shall be construed to be a tenancy from month-to-month at
one hundred twenty-five percent (125%) of the Annual Base Rental herein
specified (prorated on a monthly basis), unless Landlord shall specify a
different rent in its sole discretion, together with an amount estimated by
Landlord for the monthly Additional Rent payable under this Lease, and shall
otherwise be on the terms and conditions herein specified so far as applicable.
Any holding over without Landlord's consent shall constitute a default by Tenant
and entitle Landlord to exercise any remedies provided in Article 20 hereof or
otherwise.  Notwithstanding the foregoing, in the event Landlord consents to
Tenant's holding over and there is a resulting month-to-month tenancy under the
terms provided herein, then either Tenant or Landlord may terminate said month-
to-month tenancy upon thirty (30) days prior written notice.

     31.12  Neither this Lease nor any term or provision hereof may be changed,
waived, discharged or terminated orally, and no breach thereof shall be waived,
altered or modified, except by a written instrument signed by the party against
which the enforcement of the change, waiver, discharge or termination is sought.
Any right to change, waive, discharge, alter or modify, or terminate this Lease
shall be subject to the prior express written consent of Landlord's Mortgagee.
No waiver of any breach shall affect or alter this Lease, but each and every
term, covenant and condition of this Lease shall continue in full force and
effect with respect to any other then existing or subsequent breach thereof.

     31.13  Tenant is hereby granted non-exclusive use of the parking areas and
facilities ("Common Area") in common with other tenants, Landlord and their
respective licensees and invitees.  Landlord shall provide to Tenant, at no
additional charge, four (4) parking spaces per 1,000 square feet Rentable Area
that Tenant leases from Landlord.  Landlord reserves the right to relocate or
substitute parking areas and facilities from time to time and Landlord further
reserves the right to alter, modify and construct buildings and other
improvements within the Land or Common Areas and/or sever or subdivide the Land
or Common Areas; provided that in Landlord's reasonable judgment, the ingress
and egress to the Building and the use of the Building by Tenant shall not be
materially and substantial interfered with.  Landlord reserves the
<PAGE>
 
right to close off the Common Areas at such time and in such manner as to
prevent the public dedication thereof.  Tenant shall not park in other parking
areas.

     31.14  Notwithstanding anything contained herein to the contrary, Tenant
agrees that Landlord shall have no personal liability with respect to any of the
provisions of this Lease and Tenant shall look solely to the estate and property
of Landlord in the Land and the Building of which the Premises form a part for
the satisfaction of Tenant's remedies, including without limitation, the
collection of any judgment or the enforcement of any other judicial process
requiring the payment or expenditure of money by Landlord with respect to any of
Landlord's obligations under this Lease.  Tenant's rights under this Article
31.14 shall, however, be subject to the prior rights of the Landlord's Mortgagee
and Other Mortgagee(s) with liens covering all or part of the Land or Building.
Other than as provided in this Article 31.4, no other assets of Landlord or any
principal of Landlord shall be subject to levy, execution or other judicial
process for the satisfaction of Tenant's claim and in the event Tenant obtains a
judgment against Landlord, the judgment docket shall be so noted.  This Section
shall inure to the benefit of Landlord's successors and assigns and their
respective principals.

     31.15   Landlord shall not hold any employee, officer or director of Tenant
liable for claims or damages to the Premises under this Lease unless the claims
or damages resulted form the gross negligence or willful misconduct of the
employees, officers or directors.

     31.16  Anything in this Agreement to the contrary notwithstanding,
providing such cause is not due to the willful act or gross neglect of Landlord
or Tenant, either party shall not be deemed in default with respect to the
performance of any of the terms, covenants and conditions of this Lease, except
payment of rent, additional rent or any other payments required under this
Lease, if the same shall be due to any strike, lock-out, civil action, war-like
operation, invasion, rebellion, hostilities, military or usurped power,
sabotage, governmental regulations or controls, inability to obtain any
material, service or financing, through act of God or other cause beyond the
control of Landlord or Tenant.

     31.17  Neither Landlord nor Tenant shall record this Lease without the
written consent of the other party,  and any attempt on either party's part to
record either the Lease or a memorandum thereof without the other party's
consent first obtained in writing shall constitute an immediate Event of Default
by Tenant or Landlord (as the case may be) hereunder, entitling the other party
to pursue any and all the remedies available to it in such event.

     31.18  No reference to any specific right or remedy shall preclude Landlord
from exercising any other right or from having any other remedy or from
maintaining any action to which it may otherwise be entitled at law or in
equity.  No failure by Landlord to insist upon the strict performance of any
agreement, term, covenant or condition hereof, or to exercise any right or
remedy consequent upon a breach thereof, and no acceptance of full or partial
rent during the continuance of any such breach, shall constitute a waiver of any
such breach, agreement, term, covenant or condition.  No waiver by Landlord of
any breach by Tenant under this lease or of any breach by any other tenant under
any other lease of any portion of Building shall affect or alter this Lease in
any way whatsoever.

     31.19  Tenant, at its sole cost and expense, shall comply with and shall
cause the Premises to comply with (a) all federal, state, county, municipal and
other governmental
<PAGE>
 
statutes, laws, rules, orders, regulations and ordinances affecting the
Premises or any part thereof, or the use thereof, whether or not any such
statutes, laws, rules, orders, regulations or ordinances which may be hereafter
enacted involve a change of policy on the part of the governmental body
enacting the same, and (b) all rules, orders and regulations of the National
Board of Fire Underwriters or Landlord's fire insurance rating organization or
other bodies exercising similar functions in connection with the prevention of
fire or the correction of hazardous conditions, which apply to the Premises
except Landlord, at its sole cost and expense, shall cause the base Building
specifications of the Premises to comply with all federal, state, county,
municipal, and other governmental statutes, laws, rules, orders, regulations
and ordinances.

     31.20  If two or more individuals, corporations, partnerships or other
business associations (or any combination of two or more thereof) shall sign
this Lease as Tenant, the liability of each such individual, corporation,
partnership or other business association to pay Annual Base Rental and
Additional Rent and perform all other obligations hereunder shall be deemed to
be joint and several, and all notices, payments and agreements given or made by,
with or to any one of such individuals, corporations, partnerships or other
business associations shall be deemed to have been given or made by, with or to
all of them.  In like manner, if Tenant shall be a partnership or other business
association, the members of which are, by virtue of statute or federal law,
subject to personal liability, the liability of each such member shall be joint
and several.

     31.21  Each party warrants and represents to the other that no broker,
agent, or finder, except that shown in the Basic Lease Information, has been
involved in the transactions contemplated hereby.  Both parties hereto agree to
indemnify and hold harmless the other against any and all claims, actions,
damages, liabilities (including attorney's fees and expenses) with respect to
any commission, fee, or charge made by any broker, agent, or finder, not so
listed, which is made by reason of any action or agreement by such party.

     31.22  No payment by Tenant or receipt by Landlord of a lesser amount than
the Annual Base Rental and Additional Rent herein stipulated shall be deemed to
be other than on account of the earliest stipulated Annual Base Rental or
Additional Rent, nor shall any endorsement or statement or any check or any
letter accompanying any check or payment as Annual Base Rental and/or Additional
Rent be deemed an accord and satisfaction of Landlord's right to recover the
balance of such Annual Base Rental and/or Additional Rent or preclude any remedy
provided by this Lease.

     31.23  Any intention to create a joint venture or partnership relation
between the parties hereto is hereby expressly disclaimed.

     31.24  All agreements, covenants and indemnifications contained herein or
made in writing pursuant to the terms of this Lease by or on behalf of the
Landlord or Tenant shall be deemed material and shall survive the expiration or
sooner termination of this Lease.

     31.25  Except in the case of USAirways, Tenant shall have a right of first
refusal to lease the space contained in the Building.  The right of refusal
shall be exercised within thirty (30) days of Landlord's written notice to
Tenant of Landlord's receipt of notice of interest by a financially qualified
third party to lease such space.  Tenant shall have no right of first offer and
<PAGE>
 
Landlord need not provide Tenant with notice if an Event of Default has occurred
pursuant to Article 20.

     31.26  Disputes relating to issues regarding Landlord's performance of its
obligations hereunder shall be submitted to arbitration in accordance with the
rules of the American Arbitration Association.  The decision of the panel shall
be final and nonappealable.  No submission or right of submission of any such
matter to arbitration shall affect any other rights of the parties to judicial
determination or confession of judgment or otherwise preclude the Court of
Common Pleas of
<PAGE>
 
Allegheny County from exercising its jurisdiction over any other matter
including, but not limited to Tenant's obligations hereunder.


     IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease the day
and year first above written.

WITNESS:                            PARK RIDGE ONE ASSOCIATES,
                                    a Delaware limited partnership


                                    By:  ___________________________________
                                         a Delaware corporation
                                         General Partner

                                    By:  __________________________________
 
                                    Its:  __________________________________

                                    AUTHORIZED AGENT FOR
                                    PARK RIDGE ONE ASSOCIATES,
                                    a Pennsylvania limited partnership


ATTEST:                             MASTECH SYSTEMS CORPORATION


_________________________________    By:  ___________________________________
 
                                    Its:  ___________________________________